Question about NDPI

[Benjamin Gilbert]

On Fri, May 17, 2024 at 10:01 AM Martin Weihrauch
<m.weihrauch at smartinmedia.com> wrote:
> As the value/offset tags within the IFDs are only 4 bytes in Hamamatsu, I saw from OpenSlide that
> - If it is not the 1st IFD, then it compares the offset of any tag with the offset to the tag from the 1st IFD. If the offset is the same --> take this 32bit offset, else combine the high bits of the 64bit offset of the IFD in the file with the tag 32 bit offset to 64bits.

It turns out that this heuristic is incorrect.  Nicholas Trahearn
found that the high bits are actually present elsewhere in the file.
I haven't dug into this yet, but you can see his work at
<https://github.com/openslide/openslide/pull/602>.  I'm hoping to
switch OpenSlide to the new approach soon.

Best,
--Benjamin Gilbert